This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The endoplasmic reticulum protein Miner1 is essential for health and longevity. Mis-splicing of CISD2, which codes for Miner1, is causative in Wolfram Syndrome 2 (WFS2) resulting in early onset optic atrophy, diabetes mellitus, deafness and decreased lifespan. In knock-out studies, disruption of CISD2 leads to accelerated aging, blindness and muscle atrophy. In this work, the soluble region of human Miner1 was characterized and the crystal structure was solved to a resolution of 2.1 A (R-factor=17%). Although originally annotated as a zinc finger, Miner1 is a homodimer harboring two redox-active 2Fe-2S clusters, indicating for the first time an association of a redox-active FeS protein with WFS2. Each 2Fe-2S cluster is bound by a rare Cys(3)-His motif within a 17 amino acid segment. Miner1 is the first functionally different protein that shares the NEET fold with its recently identified paralog mitoNEET, an outer mitochondrial membrane protein.